Question

which bulb will glow

• A. 1
  
• B. 2
  
  
• C. 3
  
  
• D. 4
  
  

Answer 1

Answer: (A), (B)

The correct options are
A

1

B

2

when positive terminal of a battery is connected to negative terminal of other battery voltage will add. when positive terminal of a battery is connected to positive terminal of other battery voltages must be substracted. after doing it diodes in figure 1 and 2 are forward biased.thus bulb 1 and 2 will glow.